Accuracy and Precision of Industrial Stellar Abundances

Annual Review of Astronomy and Astrophysics

Vol. 57:571-616 (Volume publication date August 2019)
First published as a Review in Advance on July 5, 2019


There has been an incredibly large investment in obtaining high-resolution stellar spectra for determining chemical abundances of stars. This information is crucial to answer fundamental questions in astronomy by constraining the formation and evolution scenarios of the Milky Way as well as the stars and planets residing in it.

We have just entered a new era, in which chemical abundances of FGK-type stars are being produced at industrial scales, and in which the observations, reduction, and analysis of the data are automatically performed by machines. Here, we review the latest human efforts to assess the accuracy and precision of such industrial abundances by providing insights into the steps and uncertainties associated with the process of determining stellar abundances.

We also provide a description of current and forthcoming spectroscopic surveys, focusing on their reported abundances and uncertainties. This allows us to identify which elements and spectral lines are best and why. Finally, we make a brief selection of main scientific questions the community is aiming to answer with abundances.

Uncertainties in abundances need to be disentangled into random and systematic components.

Precision can be increased by applying differential or data-driven methods based on accurate data.

High-resolution and signal-to-noise spectra provide fundamental data that can be used to calibrate lower-resolution and signal-to-noise spectra of millions of stars.

Different survey calibration strategies must agree on a common set of reference stars to create data products that are consistent.

Data products provided by individual groups must be published using standard formats to ensure straightforward applicability.